Printing ink composition

Abstract

A printing ink composition that not only exerts an excellent anti-blocking effect but also is free from any hickey phenomenon, resolving the problems of form plate stain, blanket stain, etc. There are provided a printing ink composition wherein there are dispersed composite particles having a volume-average particle diameter of 2 to 8 μm in which the volume content of solid polymer particles having a particle diameter of larger than 10 μm is not larger than 5 vol. % or less. Each of the composite particles (A) comprises a solid polymer particle (B), such as wax, insoluble in the printing ink, and inorganic microparticles (C) mainly adhered to the periphery of the solid polymer particle (B) and having an average particle diameter of 5 to 1000 nm.

Description

TECHNICAL FIELD[0001]The present invention relates to a printing ink composition, and more particularly to a printing ink composition suitable for a printing ink for an offset rotary press.BACKGROUND ART[0002]It is general that the printing surface of a printed material is rubbed in contact with such as guide rolls, turn bars, a former or the back surface of another printed material immediately after printing. The rubbing causes on the printed surface a so-called blocking phenomenon that the printed ink composition is fused to adhere to the surface of the contacted substance to considerably deteriorate the quality of the printed surface and also causes a problem to contaminate the contacted surface of the other substance.[0003]To improve the abrasion resistance of the printed surface, microparticles of solid polymer such as resin or wax are added into the printing ink to form fine projections which provide the printed surface with smoothness.[0004]The printing ink on the printed sur...

AI Technical Summary

Benefits of technology

[0012](3) Provision of a printing ink composition that does not deteriorate the surface glossiness and transparency of a printing ink containing a solid polymer component for satisfying printability such as a viscoelastic property.

[0013](4) Provision of a printing ink which contains a solid polymer component exhibiting abrasion resistance and having an excellent anti-blocking effect, wherein the abrasion resistance and the blocking property are not degraded even after a process of fixing the printed surface under a high temperature.

[0014](5) Provision of an aqueous printing ink which contains a solid polymer component exhibiting abrasion resistance and having an excellent anti-blocking effect for an aqueous flexographic or gravure printing ink.

[0022]The printing ink composition of the present invention improved considerably the piling property at the time of printing, which was a problem when conventional solid polymer particles were added, and provides an excellent printed material keeping the abrasion resistance on the printed surface during and after printing.

[0023]The surfaces of the solid polymer particles (B) are coated with the inorganic microparticles (C), so that affinity with the ink vehicle is good, and a hickey phenomenon or the like is not caused.

[0025]And, the composite microparticles (A) do not degrade the transparency and glossiness of a printed material because their addition in a small amount into the ink vehicle provides a significant slip property improvement effect.

Problems solved by technology

If the volume-average particle diameter exceeds 8 μm, it is effective for improvement of the abrasion resistance and blocking property, but it is not desirable because piling occurs on the form plate, the blanket or the inking roll to cause a form plate stain or the like, and glossiness and transparency are deteriorated.

% of particles having a particle diameter of exceeding 10 μm due to a large grain size distribution are not desirable because piling tends to occur.